locks: fix locks_mandatory_locked to respect file-private locks
As Trond pointed out, you can currently deadlock yourself by setting a
file-private lock on a file that requires mandatory locking and then
trying to do I/O on it.
Avoid this problem by plumbing some knowledge of file-private locks into
the mandatory locking code. In order to do this, we must pass down
information about the struct file that's being used to
locks_verify_locked.
Reported-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Acked-by: J. Bruce Fields <bfields@redhat.com>
diff --git a/include/linux/fs.h b/include/linux/fs.h
index ae91dce..4aa81e6 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1912,6 +1912,11 @@
extern void ihold(struct inode * inode);
extern void iput(struct inode *);
+static inline struct inode *file_inode(struct file *f)
+{
+ return f->f_inode;
+}
+
/* /sys/fs */
extern struct kobject *fs_kobj;
@@ -1921,7 +1926,7 @@
#define FLOCK_VERIFY_WRITE 2
#ifdef CONFIG_FILE_LOCKING
-extern int locks_mandatory_locked(struct inode *);
+extern int locks_mandatory_locked(struct file *);
extern int locks_mandatory_area(int, struct inode *, struct file *, loff_t, size_t);
/*
@@ -1944,10 +1949,10 @@
return IS_MANDLOCK(ino) && __mandatory_lock(ino);
}
-static inline int locks_verify_locked(struct inode *inode)
+static inline int locks_verify_locked(struct file *file)
{
- if (mandatory_lock(inode))
- return locks_mandatory_locked(inode);
+ if (mandatory_lock(file_inode(file)))
+ return locks_mandatory_locked(file);
return 0;
}
@@ -2008,7 +2013,7 @@
}
#else /* !CONFIG_FILE_LOCKING */
-static inline int locks_mandatory_locked(struct inode *inode)
+static inline int locks_mandatory_locked(struct file *file)
{
return 0;
}
@@ -2030,7 +2035,7 @@
return 0;
}
-static inline int locks_verify_locked(struct inode *inode)
+static inline int locks_verify_locked(struct file *file)
{
return 0;
}
@@ -2297,11 +2302,6 @@
return (inode->i_mode & S_IXUGO) || S_ISDIR(inode->i_mode);
}
-static inline struct inode *file_inode(struct file *f)
-{
- return f->f_inode;
-}
-
static inline void file_start_write(struct file *file)
{
if (!S_ISREG(file_inode(file)->i_mode))